Parc Jean-Drapeau is one of the most visible parks in the Montreal area. The geodesic dome of the Biosphere and the Lévis tower are visible from the Old Port. The park encompasses two islands, Île Sainte-Hélène, named in honour of Hélène Boullé, the young wife of explorer Samuel de Champlain, and Île Notre-Dame, which is entirely man-made.

The islands exist in their present form due to work done in preparation for Expo 67, the international world’s fair held here in 1967. Originally, Île Sainte-Hélène had been on its own in that part of the river, with only tiny Île Ronde downstream. Île Sainte-Hélène was used by the army and later as a city park. In the early 1960s Île Notre-Dame was built alongside it, using earth and rocks dug up during excavations for the metro system.

During Expo 67 Île Notre-Dame was covered in pavilions linked by canals and footbridges. After the event was over, buildings were gradually removed from the island, leaving only the pavilions of France and Quebec, which have been renovated and linked, and turned into the Montreal Casino. The island now has a man-made beach and various bike paths as well; the official site and maps give details.

Île Sainte-Hélène was enlarged for Expo 67 but some of the parkland was preserved. East of the woodsy area, beyond the bridge, the island was built out to encompass Île Ronde to create La Ronde, an amusement park which now belongs to the U.S. chain Six Flags. After Expo 67, most of the pavilions were removed from the western end of the island, but the erstwhile U.S. pavilion, Buckminster Fuller's biggest geodesic dome, was left as a gift to the city. It has since been turned into the Biosphere, a museum and study centre about water and ecosystems. The tower and roof piece of the Korean pavilion are still standing not far from the metro station but are now barricaded; no other pavilions remain on the island.

On Île Sainte-Hélène there's also a large Alexander Calder stabile, Man, dating from Expo 67, in summertime the site of the Piknic Electronik every Sunday. A second large sculpture eastward along the shore, La ville imaginaire by Portuguese sculptor João Charters de Almeida, was given to Montreal by the city of Lisbon to mark the 30th anniversary of the metro system in 1997. There are also a number of smaller sculptures to be found in various spots in the park.

Île Sainte-Hélène has features dating back before Expo 67. The old military fort houses the David M. Stewart Museum, recently reopened after renovations, and the Lévis tower, dating from the 1930s, stands on some of the higher ground of the island and is visible from Montreal's waterfront. There's also a small military graveyard.

Despite all the installations and services in the park, Île Sainte-Hélène still has some pleasantly idyllic walks that are relatively uncrowded and unfrequented. From the higher points of the island, near the tower, there are some incomparable views of the city skyline.

To get to the park take the metro’s yellow line to metro Jean-Drapeau on Île Sainte-Hélène, and walk. From the station you can also take the 769 La Ronde (roughly June to October when the amusement park is open) or 777 Casino bus (year-round). The islands are linked by the Pont de la Concorde and by a foot bridge not far from the metro station. You can also drive to the park, taking the well-marked exit from the Jacques-Cartier Bridge in either direction; there are large pay parking lots down by the river.